JP2000028213A - Compression refrigeration machine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To eliminate the possibility of a refrigerant fluid being sent to a compressor even upon low load and upon rapid load variations in a compression refrigeration machine in which there are mutually connected through piping an evaporator, a compressor, a condenser, and a throttle valve, and a refrigerant is circulated. SOLUTION: A liquid separator 7 filled with a refrigerant absorbing/releasing agent is intervened on a piping 5 extending from an evaporator 1 to a compressor 2, and refrigerant molecules are absorbed in a first thermodynamical state where refrigerant temperature on an outlet side of the evaporator 1 is lower than refrigerant saturated vapor temperature, while the refrigerant molecules are desorbed in a second thermodynamical state where the refrigerant temperature on the outlet side of the evaporator 1 is higher than the refrigerant saturated vapor temperature. There is employed carbon dioxide as the refrigerant and there are employed as the refrigerant absorbing/desorbing agent lithium zirconate, dialkyl ether, or an amine absorption/desorption agent.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a compression refrigerator using a natural refrigerant such as carbon dioxide and ammonia as a refrigerant.

[0002]

2. Description of the Related Art Generally, a compression refrigerator has an evaporator (1), a compressor (2), a condenser (3) and a throttle valve as shown in FIG.
(4) is connected to each other by pipes (5), (51), (52) and (53) to realize a refrigeration cycle as shown in FIG. That is, the refrigerant gas from the evaporator (1) is compressed (→) by the compressor (2) to become a high-temperature, high-pressure gas,
The refrigerant gas discharged from the compressor (2) is sent to the condenser (3), where it is condensed by releasing heat to a high-temperature heat source (outside air)
(→). The high-temperature, high-pressure refrigerant liquid liquefied by condensation is supplied to the throttle valve (4), and becomes a low-temperature, low-pressure refrigerant liquid by expansion (→). The refrigerant liquid from the throttle valve (4) is sent to the evaporator (1), removes heat from the low-temperature heat source (freezer), evaporates (→), and is supplied to the compressor (2) as refrigerant gas. . By repeating the above refrigeration cycle (→→→→), heat is transferred from the low-temperature heat source to the high-temperature heat source, and the low-temperature heat source is cooled. As a refrigerant, a CFC-based refrigerant such as CFC, HCFC, or HFC is most widely used.

[0003] In a compression refrigerator, the temperature at the outlet side of the evaporator (1) is reduced as shown in FIG.
As indicated by a chain line in the drawing, the temperature may drop below the saturated vapor temperature (dry saturated vapor temperature), and some refrigerant may remain liquid.
When the mist-like refrigerant containing such a refrigerant liquid is sent to the compressor (2) and compressed ('→'), the pressure of the refrigerant becomes excessive due to the compression of the refrigerant liquid having an extremely small elastic coefficient. The compressor (2) may be damaged. So conventionally,
As shown in FIG. 7, an accumulator (6) is provided in the evaporator outlet pipe (5) so that only the refrigerant gas is supplied to the compressor (2).

The accumulator (6) comprises a cylindrical container (60) as shown in FIG. 9, and the evaporator is provided on the upper part of the container (60).
Connect the distal end of the inlet pipe (5a) extending from (1), and connect the outlet pipe (5b) whose base end protrudes vertically into the container to the bottom of the vessel. The tip of (5b) is connected to the compressor (2). Therefore, the inlet side piping
Even if the mist-like refrigerant enters from (5a), the refrigerant liquid accumulates at the bottom of the container (60), and only the refrigerant gas is sent from the outlet pipe (5b) to the compressor (2). or,
The refrigerant liquid accumulated at the bottom of the container (60) evaporates gradually and is sent to the compressor (2).

In the case of a compression refrigerator, there is a possibility that the pressure at the outlet of the compressor (2) becomes abnormally high when the load is high or the like, which causes problems such as rupture of piping. Therefore, conventionally, a safety valve (61) is provided in the compressor outlet pipe (51) so that when the pressure exceeds a threshold value and rises, gas is released from the safety valve (61) to the outside.

[0006]

In recent years, fluorocarbons such as CFC and HCFC, which have been widely used as refrigerants, have been used in recent years.
(Dupont's trade name) has become a major problem as a cause of depletion of the ozone layer and global warming, and the movement to completely abolish CFC as a refrigerant is increasing. Under such circumstances, natural refrigerants such as carbon dioxide, ammonia, and hydrocarbons are receiving attention. In particular, since carbon dioxide has no toxicity or explosive properties, its use as a refrigerant has been studied.

However, when carbon dioxide is employed as the refrigerant, the pressure on the high-pressure side of the refrigeration cycle, that is, the pressure on the outlet side of the compressor (2) is about 10 MPa, and CFC (R22) ) (About 2 MPa), the pressure on the low pressure side is about 3 MPa, and the freon (R2
In the case of 2), it will reach 5 times of (about 600 kPa).
Therefore, the compressor (2) and the piping system need to have high pressure resistance and sealing properties.

However, in the accumulator (6) used in the conventional compression refrigerator, the refrigerant liquid is stored at the bottom of the container. There is a risk that the compressor (2) may be sent to the compressor (2). In particular, in a compression refrigerator using carbon dioxide as a refrigerant, there is a high risk that the compressor (2) may be damaged by the high pressure.

In the safety valve (61) employed in the conventional compression refrigerator, the refrigerant is discharged from the safety valve (61) to the outside when an abnormally high pressure is generated. There was a problem that the refrigerant had to be refilled.

[0010] A first object of the present invention is to provide a compression refrigerating machine in which the refrigerant liquid is not likely to be supplied to the compressor even when the load is low or the load fluctuates rapidly. Further, a second object of the present invention is to provide a compression refrigerator which does not need to be refilled with refrigerant when normal operation is resumed without fear of occurrence of abnormally high pressure.

[0011]

In a compression refrigerator according to the present invention, a condenser is provided from an evaporator (1) through a compressor (2).
In the middle of the refrigerant flow path leading to (3), the refrigerant molecules are absorbed or adsorbed in the first thermodynamic state, which is an abnormal operation state, and in the second thermodynamic state, which is the normal operation state. Characterized in that a refrigerant absorbing / desorbing agent to be released is interposed.

Here, a pipe (5) from the evaporator (1) to the compressor (2) is filled with the refrigerant absorbing / desorbing agent.
(7) is interposed to absorb the refrigerant molecules in the first thermodynamic state in which the refrigerant temperature at the evaporator outlet side is lower than the refrigerant saturated vapor temperature (dry saturated vapor temperature), and the refrigerant temperature at the evaporator outlet side is By arranging to release refrigerant molecules in a second thermodynamic state higher than the saturated vapor temperature (dry saturated vapor temperature),
The first object can be achieved.

That is, when the temperature of the refrigerant supplied from the evaporator (1) to the liquid separator (7) is lower than the refrigerant saturated vapor temperature and a part of the refrigerant is liquefied, the liquid separator ( The refrigerant absorbing / desorbing agent in 7) exhibits the refrigerant absorbing ability and absorbs the liquefied refrigerant. Therefore, the refrigerant liquid does not accumulate in the liquid separator (7), and only the refrigerant gas is sent to the compressor (2). On the other hand, when the temperature of the refrigerant supplied from the evaporator (1) to the liquid separator (7) is higher than the refrigerant saturated vapor temperature,
All of the refrigerant is gasified, and the refrigerant gas is supplied to the compressor (2).
Will be sent to Also, as described above, the liquid separator
The refrigerant absorbing / releasing agent in (7) exhibits the refrigerant releasing ability, and the refrigerant molecules absorbed by the refrigerant absorbing / releasing agent are released as described above and sent to the compressor (2). As described above, the refrigerant liquid does not accumulate in the liquid separator (7), so that the refrigerant liquid remains in the compressor (2) even at a low load or a sudden load change.
There is no danger of being sent to

Specifically, when carbon dioxide is employed as the refrigerant, lithium zirconate, dialkyl ether, or an amine-based absorbent can be used as the refrigerant absorbent.

Further, piping from the compressor (2) to the condenser (3)
(51) a pressure regulator (8) filled with the refrigerant absorbing / releasing agent;
To adsorb refrigerant molecules in the first thermodynamic state where the refrigerant pressure at the compressor outlet side is higher than the normal value, and in the second thermodynamic state where the refrigerant pressure at the compressor outlet side is lower than the normal value. The above-mentioned second object can be achieved by a configuration in which the refrigerant molecules are released.

That is, when the pressure on the outlet side of the compressor (2) becomes abnormally high, the refrigerant absorbing / releasing agent in the pressure regulator (8) exhibits the refrigerant adsorbing ability and adsorbs the refrigerant. As a result, the flow rate of the refrigerant gas decreases, and the pressure decreases. Thereafter, when the cause of the pressure abnormality is eliminated and the pressure at the outlet side of the compressor (2) returns to the normal value, the refrigerant absorbing / desorbing agent in the pressure regulator (8) exhibits the refrigerant releasing ability, and As described above, the refrigerant molecules are desorbed by being adsorbed by the refrigerant absorbing / desorbing agent, and the flow rate of the refrigerant gas returns to the normal value. Therefore, even under high load, etc.
There is no fear that the pressure on the outlet side of the compressor (2) becomes abnormally high.

Specifically, when carbon dioxide is used as the refrigerant, zeolite can be used as the refrigerant absorbing / desorbing agent.

[0018]

According to the compression refrigerator of the present invention, there is no danger that the refrigerant liquid will be sent to the compressor even when the load is low or the load fluctuates rapidly. In addition, there is no fear of occurrence of abnormally high pressure, and it is not necessary to refill the refrigerant when normal operation is resumed.

[0019]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be specifically described below with reference to the drawings. As shown in FIG. 1, a compression refrigerator according to the present invention comprises an evaporator (1), a compressor,
(2) Connect the condenser (3) and the throttle valve (4) to the piping (5) (51) (52) (5
3) are connected to each other to realize a refrigeration cycle as shown in FIG. Note that carbon dioxide (CO ₂ gas) is used as the refrigerant.

A liquid separator (7) is interposed in the evaporator outlet pipe (5). In the liquid separator (7), lithium zirconate,
It is filled with a carbon dioxide absorbing / releasing agent such as a dialkyl ether or an amine-based absorbing / releasing agent. These carbon dioxide absorbing / desorbing agents absorb carbon dioxide molecules in a thermodynamic state in which the refrigerant temperature at the outlet side of the evaporator (1) is lower than the refrigerant saturated vapor temperature, and the refrigerant temperature at the outlet side of the evaporator (1) becomes lower. It releases carbon dioxide molecules in a thermodynamic state higher than the refrigerant saturated vapor temperature.

A pressure regulator is provided at the compressor outlet pipe (51).
(8) is interposed, and the pressure regulator (8) is filled with a carbon dioxide absorbing / releasing agent such as zeolite. The zeolite adsorbs carbon dioxide molecules in a thermodynamic state in which the refrigerant pressure at the compressor (2) outlet side is higher than a normal value, and emits carbon dioxide in a thermodynamic state in which the refrigerant pressure at the compressor outlet side is lower than a normal value. It releases carbon molecules. FIG. 6 qualitatively shows the relationship between the pressure P of the zeolite and the carbon dioxide adsorption amount C. When the pressure P rises from the normal value Pn to the abnormal value Pe, the adsorption amount C increases by the pressure increase. Increases by an amount ΔC corresponding to.

The liquid separator (7) is, for example, as shown in FIG.
The above carbon dioxide absorbing and releasing agent (9) in a cylindrical closed container (71)
Is connected to the upper wall of the container (71), and the distal end of an inlet pipe (5a) extending from the evaporator (1) is connected to the bottom wall of the outlet pipe (5b). The end is connected, and the tip of the outlet pipe (5b) is connected to the compressor (2). As shown in FIG. 3, an inlet pipe (5a) is connected to the upper part of the outer peripheral wall of the sealed container (71), and an outlet pipe (5a) is connected to the container bottom wall.
It is also possible to adopt a structure that combines the function of a conventional accumulator by connecting b) such that its base end protrudes to the center of the container. Furthermore, as shown in FIG. 4, if a molded product of the carbon dioxide absorbing and releasing agent (9) having one or a plurality of through holes (9a) is accommodated in the closed container (71), the refrigerant gas can be cooled. Flow resistance can be reduced. Any of the above liquid separators (7) has a simple structure and is easy to manufacture.

On the other hand, as shown in FIG. 5, the pressure regulator (8) fills the above-mentioned carbon dioxide absorbing / releasing agent (91) in a closed container (81), and the compressor ( Connect the tip of the inlet pipe (51a) extending from 2), connect the other end of the vessel to the base end of the outlet pipe (51b), and connect the tip of the outlet pipe (5b) to the condenser. It is connected to the vessel (3). Incidentally, the pressure regulator (8) can adopt the same structure as that of FIG.

In the above-mentioned compression refrigerator, the temperature of the refrigerant supplied from the evaporator (1) to the liquid separator (7) drops to, for example, about 5 ° C. at a low load or a sudden load change. When a part of the refrigerant is liquefied (the state of 'in FIG. 8),
The carbon dioxide absorbing / desorbing agent (9) in the liquid separator (7) exhibits carbon dioxide absorbing ability and absorbs the liquefied refrigerant. Therefore,
The refrigerant liquid does not accumulate in the liquid separator (7), and only the refrigerant gas is sent to the compressor (2). Thereafter, when the temperature of the refrigerant supplied from the evaporator (1) to the liquid separator (7) rises to, for example, about 10 ° C. (the state in FIG. 8), the refrigerant is all gasified, Gas will be sent to the compressor (2). Further, as described above, the carbon dioxide absorbing / releasing agent (9) exhibits the carbon dioxide releasing ability, and the refrigerant gas is released from the carbon dioxide absorbing / releasing agent (9) and sent to the compressor (2). Therefore, there is no possibility that the compressor (2) is damaged by the high pressure caused by the liquid return. Of course, the evaporator also has a large heat exchange amount and not only a sufficient refrigerating capacity can be obtained, but also the input energy of the compressor (2) is not consumed for the evaporation of the refrigerant, so that the coefficient of performance (COP) is low. improves.

When the pressure on the outlet side of the compressor (2) becomes abnormally high, the carbon dioxide absorbing / releasing agent (9) in the pressure regulator (8) is turned off.
1) exhibits the carbon dioxide adsorption ability and adsorbs the refrigerant. As a result, the flow rate of the refrigerant gas decreases, and the pressure decreases. Thereafter, when the cause of the pressure abnormality is eliminated and the pressure at the outlet of the compressor (2) returns to a normal value, the pressure regulator (8)
The carbon dioxide-absorbing / releasing agent (91) inside exhibits the carbon dioxide releasing ability, the refrigerant molecules adsorbed by the carbon dioxide-absorbing / releasing agent (91) are released as described above, and the flow rate of the refrigerant gas becomes a normal value. I will return. Therefore, even under high load, etc.
(2) There is no fear that the pressure on the outlet side becomes abnormally high, and safety is achieved. Needless to say, since the refrigerant gas is not released to the outside when an abnormality occurs, it is not necessary to refill the refrigerant when the normal operation is resumed.

The configuration of each part of the present invention is not limited to the above embodiment, and various modifications can be made within the technical scope described in the claims. For example, as the refrigerant, not only carbon dioxide but also a natural refrigerant such as ammonia can be used. In this case, it is necessary to employ a suitable absorbing / desorbing agent or an absorbing / desorbing agent according to the type of the refrigerant.

[Brief description of the drawings]

FIG. 1 is a system diagram of a compression refrigerator according to the present invention.

FIG. 2 is a sectional view of a liquid separator.

FIG. 3 is a sectional view showing another example of the liquid separator.

FIG. 4 is a sectional view showing still another example of the liquid separator.

FIG. 5 is a partially cutaway front view of the pressure regulator.

FIG. 6 is a graph showing the relationship between the pressure and the amount of carbon dioxide absorbed and released.

FIG. 7 is a system diagram of a conventional compression refrigerator.

FIG. 8 is a P (pressure) -i (enthalpy) diagram showing a refrigeration cycle.

FIG. 9 is a diagram illustrating a configuration of an accumulator.

[Explanation of symbols]

 (1) Evaporator (2) Compressor (3) Condenser (4) Throttle valve (7) Liquid separator (9) Carbon dioxide absorbing and releasing agent (8) Pressure regulator (91) Carbon dioxide absorbing and releasing agent

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Tetsuya Masuda 2-5-5 Keihanhondori, Moriguchi-shi, Osaka Sanyo Electric Co., Ltd. (72) Takashi Yamakawa 2-5-2 Keihanhondori, Moriguchi-shi, Osaka No. 5 Sanyo Electric Co., Ltd.

Claims (5)

[Claims] An evaporator (1), a compressor (2), a condenser (3), and a throttle valve (4) are connected to each other by piping so as to circulate a refrigerant. ) Through the compressor (2) to the condenser (3), in the first thermodynamic state, which is an abnormal operation state, to absorb or adsorb refrigerant molecules in the refrigerant flow path. A compression refrigerator having a refrigerant absorbing / releasing agent for releasing refrigerant molecules in a certain second thermodynamic state. 2. A pipe from the evaporator (1) to the compressor (2).
In (5), a liquid separator (7) filled with the refrigerant absorbing / desorbing agent is interposed, and the refrigerant molecules are absorbed in the first thermodynamic state in which the refrigerant temperature at the evaporator outlet side is lower than the refrigerant saturated vapor temperature. And the refrigerant temperature at the evaporator outlet side is higher than the refrigerant saturated vapor temperature.
The compression refrigerator according to claim 1, wherein the refrigerant molecules are released in a thermodynamic state. 3. The compression-type compressor according to claim 1, wherein carbon dioxide is used as the refrigerant, and lithium zirconate, dialkyl ether, or amine-based absorbent is used as the refrigerant absorbent. refrigerator. 4. A pipe (5) from the compressor (2) to the condenser (3).
In 1), a pressure regulator (8) filled with the refrigerant absorbing / releasing agent is interposed, and refrigerant molecules are adsorbed in a first thermodynamic state in which the refrigerant pressure on the compressor outlet side is higher than a normal value, and compression is performed. 2. The compression refrigerator according to claim 1, wherein the refrigerant molecules are released in a second thermodynamic state in which the refrigerant pressure on the machine outlet side is lower than a normal value. 3. 5. The compression refrigerator according to claim 1, wherein carbon dioxide is used as a refrigerant, and zeolite is used as a refrigerant absorbing / desorbing agent.